This invention relates to a DC/AC converter for igniting and supplying a gas discharge lamp. The converter has two input terminals intended to be connected to a DC voltage source and with said input terminals connected together by means of a series arrangement of a load circuit comprising at least an induction coil and a parallel arrangement of the lamp and a capacitor, as well as a first semiconductor switching element. The load circuit is shunted by a circuit comprising a second semiconductor switching element, said semiconductor switching elements being rendered alternately conducting and non-conducting by means of control circuits. A converter of this type is known from the Netherlands Patent Application No. 8400923 (which corresponds to U.S. Pat. No. 4,647,820, issued 3/3/87).
This Patent describes a high-frequency operated half-bridge converter with a discharge lamp incorporated in the load circuit. It has been found that the voltage across the lamp in the known circuit is not low enough during pre-heating of the electrodes. This is detrimental because it creates the risk of the lamp igniting on too cold electrodes, which adversely affects the life-time of the lamp.